<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Mssql.php 18951 2009-11-12 16:26:19Z alexander $
 */


/**
 * @see Zend_Db_Adapter_Pdo_Abstract
 */
require_once 'Zend/Db/Adapter/Pdo/Abstract.php';


/**
 * Class for connecting to Microsoft SQL Server databases and performing common operations.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Db_Adapter_Pdo_Mssql extends Zend_Db_Adapter_Pdo_Abstract
{
	/**
	 * PDO type.
	 *
	 * @var string
	 */
	protected $_pdoType = 'mssql';

	/**
	 * Keys are UPPERCASE SQL datatypes or the constants
	 * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
	 *
	 * Values are:
	 * 0 = 32-bit integer
	 * 1 = 64-bit integer
	 * 2 = float or decimal
	 *
	 * @var array Associative array of datatypes to values 0, 1, or 2.
	 */
	protected $_numericDataTypes = array(
	Zend_Db::INT_TYPE    => Zend_Db::INT_TYPE,
	Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE,
	Zend_Db::FLOAT_TYPE  => Zend_Db::FLOAT_TYPE,
        'INT'                => Zend_Db::INT_TYPE,
        'SMALLINT'           => Zend_Db::INT_TYPE,
        'TINYINT'            => Zend_Db::INT_TYPE,
        'BIGINT'             => Zend_Db::BIGINT_TYPE,
        'DECIMAL'            => Zend_Db::FLOAT_TYPE,
        'FLOAT'              => Zend_Db::FLOAT_TYPE,
        'MONEY'              => Zend_Db::FLOAT_TYPE,
        'NUMERIC'            => Zend_Db::FLOAT_TYPE,
        'REAL'               => Zend_Db::FLOAT_TYPE,
        'SMALLMONEY'         => Zend_Db::FLOAT_TYPE
	);

	/**
	 * Creates a PDO DSN for the adapter from $this->_config settings.
	 *
	 * @return string
	 */
	protected function _dsn()
	{
		// baseline of DSN parts
		$dsn = $this->_config;

		// don't pass the username and password in the DSN
		unset($dsn['username']);
		unset($dsn['password']);
		unset($dsn['options']);
		unset($dsn['persistent']);
		unset($dsn['driver_options']);

		if (isset($dsn['port'])) {
			$seperator = ':';
			if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
				$seperator = ',';
			}
			$dsn['host'] .= $seperator . $dsn['port'];
			unset($dsn['port']);
		}

		// this driver supports multiple DSN prefixes
		// @see http://www.php.net/manual/en/ref.pdo-dblib.connection.php
		if (isset($dsn['pdoType'])) {
			switch (strtolower($dsn['pdoType'])) {
				case 'freetds':
				case 'sybase':
					$this->_pdoType = 'sybase';
					break;
				case 'mssql':
					$this->_pdoType = 'mssql';
					break;
				case 'dblib':
				default:
					$this->_pdoType = 'dblib';
					break;
			}
			unset($dsn['pdoType']);
		}

		// use all remaining parts in the DSN
		foreach ($dsn as $key => $val) {
			$dsn[$key] = "$key=$val";
		}

		$dsn = $this->_pdoType . ':' . implode(';', $dsn);
		return $dsn;
	}

	/**
	 * @return void
	 */
	protected function _connect()
	{
		if ($this->_connection) {
			return;
		}
		parent::_connect();
		$this->_connection->exec('SET QUOTED_IDENTIFIER ON');
	}

	/**
	 * Begin a transaction.
	 *
	 * It is necessary to override the abstract PDO transaction functions here, as
	 * the PDO driver for MSSQL does not support transactions.
	 */
	protected function _beginTransaction()
	{
		$this->_connect();
		$this->_connection->exec('BEGIN TRANSACTION');
		return true;
	}

	/**
	 * Commit a transaction.
	 *
	 * It is necessary to override the abstract PDO transaction functions here, as
	 * the PDO driver for MSSQL does not support transactions.
	 */
	protected function _commit()
	{
		$this->_connect();
		$this->_connection->exec('COMMIT TRANSACTION');
		return true;
	}

	/**
	 * Roll-back a transaction.
	 *
	 * It is necessary to override the abstract PDO transaction functions here, as
	 * the PDO driver for MSSQL does not support transactions.
	 */
	protected function _rollBack() {
		$this->_connect();
		$this->_connection->exec('ROLLBACK TRANSACTION');
		return true;
	}

	/**
	 * Returns a list of the tables in the database.
	 *
	 * @return array
	 */
	public function listTables()
	{
		$sql = "SELECT name FROM sysobjects WHERE type = 'U' ORDER BY name";
		return $this->fetchCol($sql);
	}

	/**
	 * Returns the column descriptions for a table.
	 *
	 * The return value is an associative array keyed by the column name,
	 * as returned by the RDBMS.
	 *
	 * The value of each array element is an associative array
	 * with the following keys:
	 *
	 * SCHEMA_NAME      => string; name of database or schema
	 * TABLE_NAME       => string;
	 * COLUMN_NAME      => string; column name
	 * COLUMN_POSITION  => number; ordinal position of column in table
	 * DATA_TYPE        => string; SQL datatype name of column
	 * DEFAULT          => string; default expression of column, null if none
	 * NULLABLE         => boolean; true if column can have nulls
	 * LENGTH           => number; length of CHAR/VARCHAR
	 * SCALE            => number; scale of NUMERIC/DECIMAL
	 * PRECISION        => number; precision of NUMERIC/DECIMAL
	 * UNSIGNED         => boolean; unsigned property of an integer type
	 * PRIMARY          => boolean; true if column is part of the primary key
	 * PRIMARY_POSITION => integer; position of column in primary key
	 * PRIMARY_AUTO     => integer; position of auto-generated column in primary key
	 *
	 * @todo Discover column primary key position.
	 * @todo Discover integer unsigned property.
	 *
	 * @param string $tableName
	 * @param string $schemaName OPTIONAL
	 * @return array
	 */
	public function describeTable($tableName, $schemaName = null)
	{
		if ($schemaName != null) {
			if (strpos($schemaName, '.') !== false) {
				$result = explode('.', $schemaName);
				$schemaName = $result[1];
			}
		}
		/**
		 * Discover metadata information about this table.
		 */
		$sql = "exec sp_columns @table_name = " . $this->quoteIdentifier($tableName, true);
		if ($schemaName != null) {
			$sql .= ", @table_owner = " . $this->quoteIdentifier($schemaName, true);
		}

		$stmt = $this->query($sql);
		$result = $stmt->fetchAll(Zend_Db::FETCH_NUM);

		$table_name  = 2;
		$column_name = 3;
		$type_name   = 5;
		$precision   = 6;
		$length      = 7;
		$scale       = 8;
		$nullable    = 10;
		$column_def  = 12;
		$column_position = 16;

		/**
		 * Discover primary key column(s) for this table.
		 */
		$sql = "exec sp_pkeys @table_name = " . $this->quoteIdentifier($tableName, true);
		if ($schemaName != null) {
			$sql .= ", @table_owner = " . $this->quoteIdentifier($schemaName, true);
		}

		$stmt = $this->query($sql);
		$primaryKeysResult = $stmt->fetchAll(Zend_Db::FETCH_NUM);
		$primaryKeyColumn = array();
		$pkey_column_name = 3;
		$pkey_key_seq = 4;
		foreach ($primaryKeysResult as $pkeysRow) {
			$primaryKeyColumn[$pkeysRow[$pkey_column_name]] = $pkeysRow[$pkey_key_seq];
		}

		$desc = array();
		$p = 1;
		foreach ($result as $key => $row) {
			$identity = false;
			$words = explode(' ', $row[$type_name], 2);
			if (isset($words[0])) {
				$type = $words[0];
				if (isset($words[1])) {
					$identity = (bool) preg_match('/identity/', $words[1]);
				}
			}

			$isPrimary = array_key_exists($row[$column_name], $primaryKeyColumn);
			if ($isPrimary) {
				$primaryPosition = $primaryKeyColumn[$row[$column_name]];
			} else {
				$primaryPosition = null;
			}

			$desc[$this->foldCase($row[$column_name])] = array(
                'SCHEMA_NAME'      => null, // @todo
                'TABLE_NAME'       => $this->foldCase($row[$table_name]),
                'COLUMN_NAME'      => $this->foldCase($row[$column_name]),
                'COLUMN_POSITION'  => (int) $row[$column_position],
                'DATA_TYPE'        => $type,
                'DEFAULT'          => $row[$column_def],
                'NULLABLE'         => (bool) $row[$nullable],
                'LENGTH'           => $row[$length],
                'SCALE'            => $row[$scale],
                'PRECISION'        => $row[$precision],
                'UNSIGNED'         => null, // @todo
                'PRIMARY'          => $isPrimary,
                'PRIMARY_POSITION' => $primaryPosition,
                'IDENTITY'         => $identity
			);
		}
		return $desc;
	}

	/**
	 * Adds an adapter-specific LIMIT clause to the SELECT statement.
	 *
	 * @link http://lists.bestpractical.com/pipermail/rt-devel/2005-June/007339.html
	 *
	 * @param string $sql
	 * @param integer $count
	 * @param integer $offset OPTIONAL
	 * @throws Zend_Db_Adapter_Exception
	 * @return string
	 */
	public function limit($sql, $count, $offset = 0)
	{
		$count = intval($count);
		if ($count <= 0) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument count=$count is not valid");
		}

		$offset = intval($offset);
		if ($offset < 0) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument offset=$offset is not valid");
		}

		$sql = preg_replace(
            '/^SELECT\s+(DISTINCT\s)?/i',
            'SELECT $1TOP ' . ($count+$offset) . ' ',
		$sql
		);

		if ($offset > 0) {
			$orderby = stristr($sql, 'ORDER BY');

			if ($orderby !== false) {
				$orderParts = explode(',', substr($orderby, 8));
				$pregReplaceCount = null;
				$orderbyInverseParts = array();
				foreach ($orderParts as $orderPart) {
					$orderPart = rtrim($orderPart);
					$inv = preg_replace('/\s+desc$/i', ' ASC', $orderPart, 1, $pregReplaceCount);
					if ($pregReplaceCount) {
						$orderbyInverseParts[] = $inv;
						continue;
					}
					$inv = preg_replace('/\s+asc$/i', ' DESC', $orderPart, 1, $pregReplaceCount);
					if ($pregReplaceCount) {
						$orderbyInverseParts[] = $inv;
						continue;
					} else {
						$orderbyInverseParts[] = $orderPart . ' DESC';
					}
				}

				$orderbyInverse = 'ORDER BY ' . implode(', ', $orderbyInverseParts);
			}




			$sql = 'SELECT * FROM (SELECT TOP ' . $count . ' * FROM (' . $sql . ') AS inner_tbl';
			if ($orderby !== false) {
				$sql .= ' ' . $orderbyInverse . ' ';
			}
			$sql .= ') AS outer_tbl';
			if ($orderby !== false) {
				$sql .= ' ' . $orderby;
			}
		}

		return $sql;
	}

	/**
	 * Gets the last ID generated automatically by an IDENTITY/AUTOINCREMENT column.
	 *
	 * As a convention, on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2), this method forms the name of a sequence
	 * from the arguments and returns the last id generated by that sequence.
	 * On RDBMS brands that support IDENTITY/AUTOINCREMENT columns, this method
	 * returns the last value generated for such a column, and the table name
	 * argument is disregarded.
	 *
	 * Microsoft SQL Server does not support sequences, so the arguments to
	 * this method are ignored.
	 *
	 * @param string $tableName   OPTIONAL Name of table.
	 * @param string $primaryKey  OPTIONAL Name of primary key column.
	 * @return string
	 * @throws Zend_Db_Adapter_Exception
	 */
	public function lastInsertId($tableName = null, $primaryKey = null)
	{
		$sql = 'SELECT SCOPE_IDENTITY()';
		return (int)$this->fetchOne($sql);
	}

	/**
	 * Retrieve server version in PHP style
	 * Pdo_Mssql doesn't support getAttribute(PDO::ATTR_SERVER_VERSION)
	 * @return string
	 */
	public function getServerVersion()
	{
		try {
			$stmt = $this->query("SELECT SERVERPROPERTY('productversion')");
			$result = $stmt->fetchAll(Zend_Db::FETCH_NUM);
			if (count($result)) {
				return $result[0][0];
			}
			return null;
		} catch (PDOException $e) {
			return null;
		}
	}
}